Mazda is reportedly developing a hydrogen-burning rotary engine

Mazda's pledge to release more electric vehicles might not signal the end of its celebrated rotary engine. The firm is reportedly developing a hydrogen-burning Wankel that could be used to power a successor to the RX-8.

Without citing sources, Japanese magazine Best Car wrote that Mazda has never fully stopped developing the rotary engine. It significantly scaled back the program after production of the RX-8 ended in 2012, but reports circulated and even patents for rotary tech appeared in the intervening years. It expanded it again in the late 2010s to design a range extender for the MX-30 electric crossover. The development team's focus has now shifted to making a Wankel that's capable of burning hydrogen, according to the same report.

Details such as horsepower, torque, and the number of rotors haven't been released yet, likely because the engine is still at the embryonic stage of development, but it's a solution that presents several technical advantages. One of hydrogen's weak points is that it tends to ignite at heat spots inside the cylinders. Best Car noted that there are no heat spots in a Wankel engine, because it uses rotors rather than pistons, so it's well suited to burning hydrogen.

Igniting hydrogen is uncommon; most of the carmakers who dabble in the technology use the fuel to generate electricity, which then zaps one or more electric motors into motion. It's not unprecedented, however. Mazda tested and even leased experimental RX-8s whose engines could run on either gasoline or hydrogen in the 2000s, though the system took up the entire trunk and weighed nearly 200 pounds. The engine was even used in some test Mazda5 minivans. More recently, Toyota (which is working with Mazda on several projects) built a Corolla endurance race car powered by a turbocharged three-cylinder that burned hydrogen.

There's no word yet on what the new rotary would power. One possibility is the RX-Vision concept-like coupe that appeared in trademark filings in August 2021. It could arrive as a hybrid with a pair of in-wheel electric motors. If it looks anything like the 2015 concept (pictured), fans would undoubtedly welcome it as the RX-8's heir.

"If we decide to do it, the prototype will be completed within three years. The most likely system is one that combines an electric turbo," an anonymous Mazda official told Best Car. Making a prototype is relatively easy; making a business case that holds water is much more difficult. Ultimately, whether the project receives the green light for production depends on how much development will cost and whether enough people will buy the car.

Mazda hasn't commented on the report, and its future plans for the rotary engine are murky at best. There were some reports that said the range extender might have been frozen, but reports since have said that they're continuing unabated.

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